This primary aim of this Pathway to Independence Award is to provide necessary training and research experience to facilitate the PI's transition to an independent research career in the field of health and aging. The PI is a highly training sociologist and demographer seeking additional training in biology and psychology at the Andrus Gerontology Center at the University of Southern California, a preeminent research institute devoted to the study of aging. The PI will pursue a program of training and research that will add necessary knowledge of biological and psychological models of aging to the PI's current expertise in demographic health research. The objective of this award is to extend existing knowledge of how social environments 'get under the skin' and influence health by elucidating the complex associations between the neighborhood environment and psychosocial factors and their effects on health across the life course. Understanding how experiences in the social environment are translated into health risks, however, requires clarification of the biological and psychosocial processes that link social environments to health. Neighborhood-based social engagement (e.g. interactions with neighbors and participation in community organization) may represent a key, yet understudied, pathway through which neighborhoods influence older adult health. The proposed research examines the links among the neighborhood social and physical environment, social engagement, and biological markers of multi-system physiological functioning with the objective of gaining new knowledge about the specific pathways through which the neighborhood environment influences health and functioning among residents, and in particular, older residents. The application is highly significant because communities play a vital role in shaping health and well-being, particularly among older adults who may be- come more dependent on the resources and amenities in their immediate neighborhood and have greater exposure and vulnerability to neighborhood hazards. Yet, the pathways linking neighborhoods to health among older adults are not well understood. The aims of this project are to: 1) identify the psychosocial pathways linking neighborhoods to physiological dysregulation; 2) test for interactions between individual and neighborhood characteristics with respect to their effects on psychosocial functioning and physiological dysregulation; and 3) determine if neighborhood change predicts change in individual psychosocial functioning and physiological dysregulation. This project will advance understanding of the complex, multilevel determinants of the aging experience. The research objectives will be investigated through a program of secondary data analysis with several existing population-based data sets (Chicago Community Adult Health Study, Health and Retirement Study, and National Survey of Midlife Development in the U.S.), all of which integrate information on neighborhood con- text, psychosocial factors, and biomarkers. A combination of generalized linear models and multilevel methods will be used to conduct the analyses outlined in the specific aims. The skills needed to understand how biopsychosocial processes link neighborhoods and social engagement to health, which is necessary for this re- search, will be obtained as a key component of the K99 mentoring plan. The candidate will draw on a broad range of resources and training opportunities throughout the University of Southern California Andrus Gerontology Center and elsewhere to obtain the necessary skills to pursue a research career that integrates multi- level information on neighborhoods, psychosocial factors, and biological disease processes into existing re- search models in health and aging research that have traditionally focused entirely on individual-level factors. The R00 phase will allow the candidate the time needed to complete the research plan under the guidance of the candidate's K99 mentors, and to submit an R01 application to examine how the neighborhood environment and social relationships combine and interact to shape health trajectories over the life course.